640 THE PHYLOGENY OF THE FUNGI 



OTHER EUBASIDIAE SACCHAROMYCETACEAE 



HETEROBASIDIAE CORTICIUM ASCOIDEACEAE 



ENDOMYCETACEAE 

 GYMNOASCACEAE 



MYRIANGIACEAE 



/ 



ASPERGILLACEAE 

 PSEUDOSPHAERIALES, ETC. / ERYSIPHALES 



HYSTERIALES 



PEZIZALES a LEGANORALES, 



SPHAERIALES S HYPOCREALES 

 '\ 

 \ 

 \ 

 \ 

 \ 



-^ IN THESE GROUPS OCCUR 

 FORMS WITH FREE 

 AND TRICH0GYNE5 



LABOULBENIALES_---^''*^^ ™^''^ ^'^" '^'^^^ ^''"^^ 



ANCESTRAL RED SEAWEEDS 



Fig. 206. Suggested lines of evolution within the Ascomyceteae and origin of the 

 Basidiomyceteae, based upon Sachs's idea of their derivation from the Florideae. 

 (After Bessey: Mycologia, 34(4):355-379.) 



(i.e., the typical i'our-spored basidium). The "conidial" Phycomyceteae 

 (some Mucorales, the Entomophthorales, etc.) were looked upon as the 

 origin of the Basidiomycetous hne. Although this Brefeldian hypothesis 

 has become discredited with the demonstration of the actual occurrence 

 of sexuality in the higher fungi and by the general acceptance of the 

 homologies of ascus and basidium and of the crozier and clamp connec- 

 tions his theory still exerts a strong influence in most systems of classifica- 

 tion of these fungi. 



With the acceptance of true sexuality in the higher fungi various 

 mycologists have turned to the morphologically simple families of the 

 Ascomyceteae as probably representing the intermediate stages between 

 the Phycomyceteae and the Ascomyceteae. The discovery by Lagerheim 

 (1892) of Dipodascus albidus and the careful working out by Juel (1902) 

 of the (;ytology of its sexual reproduction have revealed a form that lends 

 itself well to consideration as such a link. In this fungus the mycelium is 

 septate, each segment being coenocytic. Usually adjacent segments pro- 

 duce upright, multinucleate gumetangia which unite near their apices. A 

 "privileged nucleus" of each gametangium unites with the corresponding 

 one from the other to form a large zygote nucleus. From the junction of 



